A Communist and a Scottish nationalist, the poet Hugh MacDiarmid (1892–1978) was, in the words of Bob Purdie, ‘a man in constant revolt’ against the Scottish culture of his day. This study of MacDiarmid’s politics discusses his relationship to fascism and right-wing ideas in the 1920s; his involvement with Social Credit; his participation in Scottish nationalist politics in the 1920s and 1930s; his Marxism; and his politics during and after the Second World War.